Infectious granulomatous dermatitis: A clinico pathological study

Granulomatous dermatitis frequently presents a diagnostic challenge to dermatopathologists as an identical histologic picture is produced by several causes. Present study aims at classifying infectious granulomatous dermatitis based on etiology and morphology of granulomas, and to highlight significance of clinical correlation in making a specific diagnosis. A retrospective analysis of skin biopsies was done and cases of infectious granulomatous dermatitis diagnosed on histopathological examination were retrieved. A total of 586 cases of granulomatous dermatitis were retrieved; out of these, on the basis of clinico-pathological findings, 515 cases (87.8%) were categorized as infectious granulomatous dermatitis. The age of the patients ranged from 7-80 years with a male to female ratio of 1.5:1. Majority of the cases were of leprosy (373 cases, 72.4%) which were further classified into sub-groups according to Ridley and Jopling. Second largest group was of cutaneous tuberculosis including tuberculids (119 cases, 23.1%). Fungal dermatitis was diagnosed in 17 cases (3.3%) and 6 cases (1.16%) were diagnosed as post kala-azar dermal leishmaniaisis based on the lympho-histiocytic and plasma cell inflitrate. Infections form an important cause of granulomatous dermatitis with leprosy and tuberculosis as the leading causes. Adequate clinical data and workup in combination with pathological resources can help in elucidation of specific etiology and good clinicopathologic correlation